Inheriting the folk tradition of the protest song, rock music has been associated with political activism as well as changes in social attitudes to race, sex and drug use, and is often seen as an expression of youth revolt against adult consumerism and conformity. It is "not driven by any significant ambition except profit and commercial reward … Unlike many earlier styles of popular music, rock lyrics have dealt with a wide range of themes in addition to romantic love: including sex, rebellion against "The Establishment", social concerns and life styles. These themes were inherited from a variety of sources, including the Tin Pan Alley pop tradition, folk music and rhythm and blues. Music journalist Robert Christgau characterizes rock lyrics as a "cool medium" with simple diction and repeated refrains, and asserts that rock's primary "function" "pertains to music, or, more generally, noise." The predominance of white, male and often middle class musicians in rock music has often been noted and rock has been seen as an appropriation of black musical forms for a young, white and largely male audience. As a result, it has been seen as articulating the concerns of this group in both style and lyrics. Like pop music, lyrics often stress romantic love but also address a wide variety of other themes that are frequently social or political in emphasis. Rock music is traditionally built on a foundation of simple unsyncopated rhythms in a 4/4 meter, with a repetitive snare drum back beat on beats two and four. Melodies are often derived from older musical modes, including the Dorian and Mixolydian, as well as major and minor modes.
It has also made use of technological innovation. As a genre, pop music is extremely eclectic, often borrowing elements from other styles including urban, dance, rock, Latin and country; nonetheless, there are core elements which define pop. Rock music is a genre of popular music that originated as "rock and roll" in the United States in the 1950s, and developed into a range of different styles in the 1960s and later, particularly in the United Kingdom and the United States. It has its roots in 1940s' and 1950s' rock and roll, itself heavily influenced by blues, rhythm and blues and country music. Similarly, 1970s punk culture spawned the visually distinctive goth and emo subcultures. In the 1940s improved microphone design allowed a more intimate singing style and ten or twenty years later inexpensive and more durable 45 r.p.m.
Harmonies range from the common triad to parallel fourths and fifths and dissonant harmonic progressions. Rock songs, since the late 1950s and particularly from the mid-1960s onwards, often used the verse-chorus structure derived from blues and folk music, but there has been considerable variation from this model. Critics have stressed the eclecticism and stylistic diversity of rock. Because of its complex history and tendency to borrow from other musical and cultural forms, it has been argued that "it is impossible to bind rock music to a rigidly delineated musical definition. Classically, a rock band takes the form of a quartet whose members cover one or more roles, including vocalist, lead guitarist, rhythm guitarist, bass guitarist, drummer and often that of keyboard player or other instrumentalist. The terms "popular music" and "pop music" are often used interchangeably, although the former is a description of music which is popular (and can include any style). The terms "popular music" and "pop music" are often used interchangeably, although the former is a description of music which is popular (and can include any style). Rock music is traditionally built on a foundation of simple unsyncopated rhythms in a 4/4 meter, with a repetitive snare drum back beat on beats two and four. Melodies are often derived from older musical modes, including the Dorian and Mixolydian, as well as major and minor modes. According to Grove Music Online, the term "pop music" "originated in Britain in the mid-1950s as a description for rock and roll and the new youth music styles that it influenced …". The Oxford Dictionary of Music states that while pop's "earlier meaning meant concerts appealing to a wide audience … Typically, rock is song-based music usually with a 4/4 time signature using a verse-chorus form, but the genre has become extremely diverse. Rock musicians combined an emphasis on skill and technique with the romantic concept of art as artistic expression, original and sincere". In the new millennium the term rock has sometimes been used as a blanket term including forms such as pop music, reggae music, soul music, and even hip hop, with which it has been influenced but often contrasted through much of its history.. Musically, rock has centered on the electric guitar, usually as part of a rock group with electric bass guitar and drums. Throughout its development, pop music has absorbed influences from most other genres of popular music.